Purpose: Disruption of coronary artery plaque is the primary cause of acute coronary syndrome(ACS). The vulnerable, rupture-prone plaques are characterized by large plaque volumes and large necrotic cores with thin fibrous caps. The positive remodeled vessels and small calcific concretions in fibrous cap have been shown to contribute to plaque instability. We evaluated characteristics of culprit coronary lesions between ACS and stable angina pectoris(SAP) using multislice computed tomography(MSCT)Methods: 64-slice MDCT was conducted on 37 patients with 18 patients with ACS and 19 patients with SA before percutaneous coronary intervention (PCI). The culprit coronary lesions were evaluated for signal intensity of plaque, spotty calcification, outer vessel diameter and area in culprit lesion characteristics and remodeling index(RI). The remodeling index was defined as the ratio of lesion diameter and mean of proximal and distal reference diameter. Results: In patients with ACS, culprit coronary lesions had significantly higher remodeling index than patients with SA(p < 0.001). The plaque of culprit coronary lesions in patients with ACS were predominantly non-calcified(46% vs 32%, p=0.02) In addition, lower SI and more spotty calcification were observed in the plaque of culprit lesions in patients with ACS(p = 0.02, p < 0.001).Conclusions: In our study, the culprit lesions of ACS had higher remodeling index, lower SI of plaque and spotty calcification.